The Guerbet reaction has hitherto been known as a method for preparing a branched alcohol by dimerizing an aliphatic monoalcohol.
Generally, this reaction is thought to proceed by the combination of a mechanism that involves the abstraction of hydrogen from a starting alcohol in the presence of a basic compound and a catalyst (hydrogen transfer reaction) to form the corresponding aldehyde intermediate, a mechanism in which the aldehyde intermediate is dimerized via aldol condensation to form an α,β-unsaturated aldehyde intermediate, and a mechanism in which hydrogen is added to the α,β-unsaturated aldehyde intermediate (Hydrogen transfer reaction) to form an alcohol (see, for example, Non-Patent Document 1).
It is known that the Guerbet reaction proceeds at a relatively good yield when a linear alcohol is used as the starting material, but that the yield of the target compound tends to decrease when a branched alcohol is used as the starting material, perhaps on account of a decrease in reactivity due to steric hindrance by the branched alcohol.
Were it possible to improve the yield here, this would lead to a large reduction in production costs. Hence, improving the yield of the Guerbet reaction is an important concern in terms of establishing an industrial production process.